GB776008A - Improvements in or relating to constant voltage apparatus - Google Patents

Abstract

776,008. Transformers; automatic regulation. SOLA ELECTRIC CO. Oct. 25, 1954 [Nov. 6, 1953], No. 30649/54. Classes 38 (2) and 38 (4). A high reactance, limited current, transformer for use in a system in which a load is required to be supplied with a constant voltage irrespective of supply voltage variations comprises a main core member 14 around which is placed a secondary winding 12; one or two auxiliary core members-as shown two members 15, 16- being placed at one or either side of the winding 12, the primary winding 11 then being wound over the core members and the secondary winding in toroidal form and lastly the whole assembly having a toroidal auxiliary winding 13 wound thereover. The core members are all formed from spirally wound magnetic strip and may if desired be cut to provide air gaps in the magnetic circuit. A condenser 24 (see Fig. 8) is connected across the ends of the secondary winding 12 such that when the normal operating voltage is applied to the primary winding 11 the core 14 saturates and causes series resonance in the circuit including the winding 12 and condenser 24. Any change in the voltage applied to the primary winding 11 will then have little effect on the voltage appearing across the secondary winding 12; what little effect there is is eliminated in a load circuit 28 by connecting the winding 13 in series opposition to the winding 12 or, since the voltage across the winding 12 is very high due to the resonance, the part of the winding 12 between the terminal 25 and the tapping 27.